There seems to be a vast concern lately about spyware and adware, some of which places things that compromise your security on your machine.
Others will simply keep downloading links that are making someone rich while your computer slows down to a disgusting crawl that you can’t seem to recover from.
There are some great free spyware and adware programs, and also a few online places to go where you can test your own computer to see if you’ve been affected by adware or spyware in any way.

Some places to go and test your computer for spyware and other problems are :

Symantec Security Check.
Test your computer for vulnerabilities and learn how to keep it secure.

Panda Software Scan
(scroll to the bottom of the page for the scanner)

Zone alarm free version firewall.

If you are concerned that you might have a problem on your computer with spyware or adware, take steps to check into it, and to secure a good adware software, or a good firewall software.